Flashlight lamp



Oct. 16, 1951 J. H. M. VAN UDEN ET AL 2,571,799

FLASHLIGHT LAMP Filed Feb. 14, 1948 JULES HENRI MARIE van UDEN GERARD DANIEL RIECK INVENTORS AGENT Patented Oct. 16, 1951 UNITED STATES PATENT OFFICE FLAS'HLIGHT LAMP Jules Henri Marie van Udeiiand Gerard" Danie? Bieck, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company; Hartford, Conn as trustee" Application February 14, 1948, Serial 9. 8,384 In the Netherlands March 3, 1947 8 claims. i

This invention relates to flash-light lamps which are electrically ignited and in which the actinically reacting material is provided in a bulb.

With such flash-light lamps it is customary to initiate the electric ignition by means of a small electric incandescent member which causes an associated mass of an ignition paste to react'.

The present invention uses a difierent principle with a result that such a separately fitted electric incandescent member is superfluous and, as the case may be, even the ignition paste can be omitted.

According to the invention use is made of a member of electrically conducting actinically reacting material which member interconnects the supply conductors, and a portion thereof acts' as an ignition member.

The use of a filament of actinically reacting material, interconnecting the supply conductors has been known for a long time (German Patent 297,329). However, this construction has several disadvantages. Primarily the mounting of the filament involves difficulties, since it is required that the filament. of actinically reacting material either to be provided on eyelets secured to the supply conductors or to be used in the form of a clew contacting the supply conductors, which constructions are susceptible to the risk'of' short circuits. With a given source of electrical energy one is' furthermore very limited in choosing thequantity and size of the actinically reacting material required" for ensuring a satisfactory ignition.

The present invention is different from what is known in the art, since part of the bo'dy'o'f the actinically reacting material functions as an ignition member, so that the main mass of the body may be given a comparatively liberal form thereby permitting an accurate control of the flashing time.

In order that the invention may be clearly understood and readily carried into effect it will now be explained more fully with reference to the accompanying drawing, in which:

Figure 1 is an elevation of a photoflash lamp comprising my invention; and Fig. 2 is a sectional view, on an enlarged scale, of the strip of combustible material employed in the lamp shown in Figure 1.

In this drawing the reference numeral I denotes the bulb of a flash-light lamp which comprises supply conductors 2 interconnected by a magnesium strip 3 comprising two portions 5 of given width connected by a portion 4 having a width smaller than said given width formed for instance by aunching. Th s narrowed portion war have a higher overall electrical resistance than the main body portion 3' and thus the passage of current at a sufficien't voltage immediately produces a chemical reaction between the magnesium in the portion 4 and the" oxygen filling. This chemical reaction initiates the chemical reaction of the whole magnesium body 3' as is required for the actinic effect. I

The referenc-numerai' 5' denotes a fuse which prevents any undesired arc-formation at 4 and of which the resistance is sufii'cie'n't' for preve t: ing too vigorous a reaction due to which incoiil'i bustedr'netal particles mig'ht deposit on the wall of the bulb. At an ignition voltage of zowcns a resistance of several ohms issufiicient. For example at anapplied potential of 220 volts a resistance of 2 ohms is' generally satisfactory, while at low potentials in the neighborhood of volts, no resistance need be added for the circu t resistance is itself suificient' to prevent are formation at the low potential.

The shape or the actinically reacting member as shown in the accompanying is suitable for" obtaining a long flashing time with maximumintensity.

The cross-sectional area of the portion 4" is determined by the voltage of the; ignition source. In the case-ofa low ignition voltage such as provided by a pocket lamp battery or of a 4-volt battery the use ofzirconiumhas advantages over magnesium as the actinically reacting material. since with zirconium the required accuracy insize is smaller than in the case of magnesium.- As' an example we may mention that in the case of a magnesium strip 3- having, for instance, athickness of 20- microns itisrequ-ired for ignition bymeans of a pocket lamp battery: that the ign i.- tion area" 4" should have a lengthof appr,oi imately 7 millimeters and a width of appraisi-- mately 0.2 millimeter. When ignition is to be effected by means of a 4-volt battery and the said length of the ignition area is 7 millimeters, a width of approximately 2 millimeters is required, whereas for a main voltage of 220 volts a much smaller length and a width of /2 millimeter is sufficient.

Finally, in using the invention one may also use ignition paste provided at the point, of ignition, in which case one is less bound to accuracy in proportioning the ignition area 4.

What we claim is:

1. An electrically ignited flash lamp comprising a container, a combustion-supporting filling within the container, electrical supply conducgerms tors extending into the container, and a member of electrically conducting actinically-reacting material secured to said supply conductors within the container, said member comprising a first flash producing portion and a second ignition portion integral with said first portion and having a cross-sectional area smaller than said first portion and an overall electrical resistance greater than that of said first portion.

2. An electrically ignited flash lamp comprising a container, a combustion-supporting filling within the container, electrical supply conductors extending into the container, and a member of electrically conducting actinically reacting material within the container, said member comprising flash producing portions secured to said supply conductor and an ignition portion interconnecting the flash producing portions and having a cross-sectional area smaller than the flash producing portions and an over all electrical resistance greater than that of said flash producing portions.

3. An electrically ignited flash lamp comprising a container, a combustion-supporting filling within the container, electrical supply conductors extending into the container, and a member of electrically conducting actinically reacting material within the container, said member comprising strip-shaped flash producing portions each having one end secured to said supply conductors and an ignition portion interconnecting the other ends of the said flash producing portions and having a cross-sectional area smaller than the flash producing portions and an overall electrical resistance greater than that of said flash producing portions.

4. An electrically ignited flash lamp comprising a container, a combustion-supporting filling within the container, electrical supply conductors extending into said container, and a U- shaped strip of electrically conducting actinically reacting material within the container, said strip having the arm portions thereof secured to said supply conductors and the yoke portion thereof having a cross-sectional area smaller than the cross-sectional area of the said arm portions and an overall electrical resistance greater than that of said arm portions.

5. An electrically ignited flash lamp comprising a container, a combustion-supporting filling within the container, electrical supply conductors extending into said container, and a U-shaped strip of magnesium within the container, said strip having the arm portions thereof secured to said supply conductors and the yoke portion thereof having a cross-sectional area smaller than the cross-sectional area of the said arm portions and an overall electrical resistance greater than that of said arm portions.

6. An electrically ignited flash lamp compris ing a container, a combustion-supporting filling within the container, electrical supply conductors extending into said container, and a U- shaped strip of zirconium within the container, said strip having the arm portion thereof secured to said supply conductors and the yoke portion thereof having a cross-sectional area smaller than the cross-sectional area of the said arm portions and an overall electrical resistance greater than that of said arm portions.

7. An electrically ignited flash lamp comprising a container, a combustion supporting filling within the container, electrical supply conductors extending into the container, a member of electrically conducting actinically-reacting material secured to said supply conductors within the container and comprising a first flash producing portion and a second ignition portion integral with said first portion and having a cross-sectional area smaller than said first portion, and an ignition paste body on said second portion and an overall electrical resistance greater than that of said first portion.

8. An electrically ignited flash lamp comprising a container, a combustion-supporting filling Within the container, electrical supply conductors extending into said container, a member of electrically conducting actinically reacting material secured to said supply conductors within the container, said members comprising a first flash producing portion and a second ignition portion integral with said first portion and having a cross-sectional area smaller than said first portion and an overall electrical resistance greater than that of said first portion, and a resistance element connected in series with one of said supply conductors.

JULES HENRI MARIE VAN UDEN. GERARD DANIEL RIECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,776,637 Ostermeier Sept. 23, 1930 2,003,660 Yamaguchi et al.' June 4, 1935 2,037,101 Van Liempt Apr. 14, 1936 2,057,583 Mey Oct. 13, 1936 2,156,057 Krefit Apr. 25, 1939 2,183,952 Anderson Dec. 19, 1939 2,263,179 Lockwood Nov. 18, 1941 FOREIGN PATENTS Number Country Date 297,329 Germany Apr. 11, 1917 

